In current engineering practice, the specification and control of density and moisture of earthen fill is typically based on the results of the Standard Proctor compaction test (American Society for Testing Materials [ASTM] D698) or the Modified Proctor compaction test (ASTM D1557), or other similar test standards derived from the Proctor tests and established by other institutes and governments (i.e. AASHTO, etc;). All standard tests used in practice utilize fixed soil compaction energies. The compaction energy used in the standard proctor compaction test is 600 kilonewton-meter per cubic meter Kn-m/m3 or 12,400 foot pounds per cubic foot (ft-lbs/cf). The other standard tests based on the Standard Proctor Test use the same or comparable fixed energy levels. These standard tests are based on work by R. R. Proctor, who estimated field compaction energies of towed compactors (or rollers) used in the early 1930's. These fixed compaction energy levels were based on drawbar pull values measured with towed compactors, and considered to be somewhat representative of field compaction energies. Subsequently, it was found that high fills constructed by using the standard proctor energy experienced substantial compression under their own weight. This fill compression combined with the development of aircraft and truck traffic with heavier wheel loading led to the development of the modified proctor compaction test by R. R. Proctor. Hunt, R. E. (1986) Geotechnical Engineering Analysis and Evaluation, McGraw-Hill Book Co., p.211. The compaction energy used in ASTM D1557 (2,700 Kn-M/m3, or 56,000 ft-lbs/cof) is about 4.5 times higher than the compaction energy used in ASTM D698.
Even in the 1930's and 1940's it was recognized that the laboratory compaction tests produced energies that were inconsistent with field compaction energies. Numerous attempts were made to develop test procedures that produced field and laboratory compaction (moisture-density) curves that would be more comparable. The present inventors have published a very basic approach to improved procedures: 1.) “Practice Improvements for the Design and Construction of Earth Fills”, Proceedings of the Eighth Annual Conference on Contaminated Soils, University of Massechusetts at Amherst, 1994; and Geoenvironment 2000 Conference, New Orleans, La., 1995; and 2.) “Practice Improvements for the Design and Construction of Earth Fills”, Proceedings of the Texas Section Fall Meeting, 1995, American Society of Civil Engineers, El Paso, Tex. There has not previously been available in the art practicable methods to derive actual cumulative field compaction energies unique to each site based on soil/compactor/lift thickness/moisture/soil amendment combinations, a data matrix developed to provide actual field combination-specific compaction energy levels and engineering property correlations based on variable soil/compactor/moisture/lift thickness combinations, or to allow extrapolation for intermediate combinations or compaction conditions, with or without field data, or to select field-specific compaction energy levels to be applied in laboratory tests or utilized in engineering methods, rather than the fixed energies of the standard test methods described above. The new improvements provide a different method for modeling of actual, combination-specific field compaction energies in the laboratory that are not fixed, and provide for design applications and specifications, and construction, for all types of compactors combined with all classes of earthen fills (having a suitable fines fraction) moisture states, lift thickness', and soil amendments.